Network-type game systems, in each of which a server controls operations of a plurality of game devices connected via a network, have been widely used. In a game realized by such a game system, a professional wrestler, registered with an entity managed by a player who operates a game device, plays a match against another professional wrestler registered with another entity managed by another player who operates another game device, as described in “Battle Climax”, Monthly Arcadia Magazine, June (Serial No. 49), Japan, Enterbrain Inc., Jun. 1, 2004, Vol. 5, No. 6 (Serial No. 49), pp. 24-31.
This game system uses wrestler cards for executing games. On a wrestler card, information is recorded about a wrestler as a character (game character) that will be used in games. A wrestler card is necessary for a player to register the wrestler recorded on the wrestler card with an entity of the player by operating a game device. Accordingly, if a player has more various types of wrestler cards, the player can select preferred wrestlers from among various wrestlers and register the wrestler with the player's entity, and therefore a greater diversity of choices is available. By virtue of this worth, wrestler cards are regarded as collectibles. The game system provider has been preparing several hundred wrestler cards. The wrestler cards can be treated as trading cards that can be exchanged among players. This feature is an important factor for enriching a fascinating aspect of games.